Electrical condenser unit



Aug. 9, 1932- w. DUBILIER 1,870,948

ELECTRICAL CONDENSER UNIT Original Filed June 11, 1924 I l I I i 3 Z 7 E f E g I I 1 /I !i\ p g J a,

mvmmn William Dubilz'er H TTIORNEY Patented Aug. 9, 1932 UNITED STATES WILLIAM DUBILIER, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO DUBILIER CON- l DENSER CORPORATION, OF NEW YORK, N.'Y., A CORPORATION OF DELAWARE ELECTRICAL CONDENSER UNIT Original application fiIed Jun e 11, 1924, Serial No. 719,335. Divided and. this application filed March 19, 1926. Serial No. 96,097.

This invention relates to an improved condenser element for use with alternate layers of conductive material and of dielectric, in the building up of condenser stacks.

It is intended to be interspersed at frequent intervals among such alternating layers and forms as essential a part of the completed stack as do the alternating layers.

This invention is particularly adapted for high efliciency types of condensers which are employed on high power, short wave circuits and which are soefficient and compact that the stacks become unduly short without the use of the herein described units and would be liable to flashover or electric discharge past the edges of thealternating layers of conductive material and dielectric, without said units.

The condenser element has, of course, other uses and it is obvious that it can be used as a mere spacer in some situations. This application is a continuation in part of my copending application No. 719,335, filed June 11, 1924, for electrical structures.

An object of the invention is to provide a condenser element which is electrically conductive and which can be made in any desired size or thickness without being entirely of metal; and which has other advantages mentioned in the specification that follows; and I, of course, reserve the right to vary the structure actually shown herein, without departing from the nature of the invention or exceeding' its scope, as defined in the appended claims.

On the drawing,

Figure l is a top view of the core for my improved condenser element;

Figures 2 and 3 are plan views of sheets of conductive material, such as metal foil in which this core is wrapped;

Figure 4 is a perspective view showing the core with one of the wrappings partly in place;

Figure 5 is a similar view showing the core with one wrapping in place, and the other partly in place;

Figure 6 is a perspective view of the finished element when both wrappings are on same; and

to provide this core is to superpose a number of sheets of mica, until the required thickness has been obtained. Another convenient way is to mould it out of a phenolic condensation product. Then I partly enclose this core by wrapping around it a sheet 2 of some conductive material such as metal foil. This sheet may extend lengthwise of the core covering one face, with its ends turned over the two extremities of the core, down upon the opposite face. will thus have transverse portions 4 which engage the two opposite ends of the core, and the extremities 5 will lie flat against the outside of the core thus encircling the core lengthwise. After the wrapping 2 is attached, this core is further covered by putting around it the sheet 3 of metal foil, this sheet being so disposed, that it extends at right angles with respect to the sheet 2, that is, over the width of the core, the middle of the sheet 3 engaging the sheet 2 as indicated in Figure 5, and having transverse portions 6 which will lie against the two opposite sides of the core 1 and with ends 7 that are folded down on top of each other and thus cover the ends 5 of the sheet 2. The complete element will then appear as in Figure 6 and will consist of a core of insulation with one or more wrappings of conductive material.

This element can be utilized in a variety of ways within the body or stack of the condenser.

Figure 7 shows a stack of a condenser made up of sheets or plates of insulation between conductive elements or armatures 10 with elements 11 at the two ends or terminals of the stack and in contact with the terminal armatures 10 which engage blocks 11. Each of these elements will have the same construction as the unit shown in Figure 6; and Figure 8 shows a number of sections 12 made This sheet or wrapping 2 Y of the condenser in which it is to be located.

may require, The metal wrappings where they extend across the corners of the core will be more or less rounded due to the softness of the en closing foil and thus the el ment will have no sharp edges to facilitate sparking in the condenser. On account of the insulating core, it has less tendency to heat up when in use and thus it facilitates reducing the losses of the condenser in which it is placed, and at the same time, it can be made as large as desired, while the metallic exterior gives .it electrical conductivity, and the ability to have electrostatic effect, the same as the armatures 10.

A very important factor in the type of high efliciency condenser. in which the herein described condenser element is most useful. is creepage distance. Referring to Fig. 8, reference numeral 12 indicates three groups or stacks of alternating layers of conductive foil and dielectric. Each of these groups consists of any where from three to a dozen sheets of foil separated by intervening dielectric these sheets of foil are isolated. That is, all of the sheets are alike and all four edges of each sheet are spaced inward from the edges of the mica or sheets of dielectric. This arrangement is quite dili erent from the usual one in which alternate sheets of foil project out from the opposite edges of the laminated stack. As a result of this isolation feature, the electric forces penetrate in at right angles to the, sur aces of the plates and this cuts down heating eflects compared with the other arrangement in which the current passes in from projecting ends of the foil and flows in the plane of the sheets to get to the interior of the s ack.

This isolated foil arrangement does not directly form a part of the present invention, but concerns it to the extent that the arrangement results in such great efliciency and compactness that the creepage distance in prior constructions of this type, across the ed es of the dielectric sheets from one end foil to the opposite end foil becomes short and the current is bound to flash over the ends and short circuit. In Figure 8, reference numerals 11 indicate the conductive blocks or con denser elements that are the subject of the present application and the figure shows them disposed. between the several groups 12 of the active parts of the condenser.

The effect of these blocks is to greatly increase the creepage distance, for, instead of the current passing from the edge of the sheets of dielectric material.

terminal foil to the edge of the corresponding end sheet of dielectric then straight across the edges of all the sheets of dielectric to the edge of the opposite end sheet and down to the edge of the corresponding opposite terminal foil; with the elements 11 present, the current must at frequent intervals travel in ward from the edge of one of the dielectric sheets to the edge of the element or block 11, andv then travel outwardly from the edge of block 11. to the edge of another one of the After having traversed the full depth and height of several of these intervening recesses, instead of going strai ht across all the edges, the creepage distance becomes so great that the current cannot follow the same and therefore does not flash over or short circuit.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States is l. A condenser member comprising a core of insulation, and a pair of wrappings for said core, said wrappings being transversely arranged with respect to each other, and one enclosing the other.

2. A condenser comprising a stack of alternate layers of conductive and dielectric material serially arranged between terminals, and a block of insulating material disposed in said stack at a point intermediate said terminals and having conductive layers on opposite sides thereof, said block dividing the stack into a plurality of serially-connected sections.

3. .A condenser comprising a stack of alternate layers of conductive and dielectric material serially arranged between terminals, and a block of insulating material disposed in said stack at a point intermediate said terminals thereby dividing the said layers into groups, said block having greater thickness than the conductive sheets and smaller area than the dielectric sheets and having a con ductive coating thereon for electrically connecting said groups in series.

In testimony whereof I aflix my signature.

' WILLIAM DUBILIER. 

